Colicin E2

Colicin E2 is a type of Colicin, a bacteriocin made by E. coli which acts against other nearby E. coli to kill them with its DNase activity; it digests the host genome, leading to its death.

Synthesis and release
The ColE2 operon is encoded on a plasmid in E. coli, alongside its Colicin Immunity Protein, Imm. This protects the colicinogenic cell from the cytotoxic activity of the colicin.

Mechanism of uptake
Colicin E2 binds to the BtuB receptor on the target E. coli cell to begin its translocation across the membrane. This structure shows the binding between BtuB (blue) and the Colicin E2 receptor binding domain (green). After binding to the BtuB receptor, the immunity protein is released from the cytotoxic domain prior to translocation across the membrane.

Killing Activities
Colicin E2 kills its target cell, after leaving behind the immunity protein at the cell surface, with its DNase Activity found in its C terminal cytotoxic domain.